Medical and paramedical personnel engaged in the practice of emergency medicine and medical personnel in operating rooms and in intensive care units must be ready to face a broad spectrum of problems and challenges presented by traumatized patients. Particularly important is the ability of such medical personnel to respond to life threatening air passage blockage, injuries and diseases. Many of these conditions appear with little or no warning, and they must be dealt with immediately if further trauma is to be avoided. Often there is little or no time for consultation with an experienced specialist. For this reason, emergency room medical personnel are trained to quickly react to and treat air passage problems whenever and wherever they occur. In many cases, accident victims respond well to relatively simple basic maneuvers such as suction or positioning the head and jaws to free the oropharyngeal and nasopharyngeal areas from any gross obstructions which might be present. In still other cases positive pressure ventilation, such as the use of mouth-to-mouth breathing, or the use of various ectotracheal devices such as esophageal obturators, demand-mask or bagvalve-mask devices will suffice.
There are times, however, when the patient exhibits much more serious conditions, such as those in which large tumors or severe facial injuries partially or even totally block access to the upper trachea. When this happens, more advanced procedures are required. In many of these cases, the use of insufflation techniques such as orotracheal or nasotracheal intubulation coupled with the application of low pressure oxygen will provide sufficient ventilation. However, in those patients exhibiting massive facial trauma, or when there is either a laryngeal stenosis lying below the vocal cords or a major tracheal obstruction, such techniques often will not provide a level of ventilation adequate to prevent respiratory acidosis. In such situations, a number of alternate endotracheal techniques, such as cricothyroidotomy and tracheostomy have been described in the prior art; however, time, experienced personnel and specialized equipment are required to apply them. Further, even when appropriately applied, permanent scarring may result.
For the most drastic situations, two other methods have been described for emergency endotracheal airway management. These involve the delivery of oxygen to the lungs via a translaryngeal or transtracheal puncture and the use of a percutaneously placed catheter to provide either (1) continuous low-flow insufflation or (2) high pressure jet-flow ventilation. Problems reported with continuous low-flow insufflation are carbon dioxide retention and respiratory acidosis. While Jet ventilation produces better results, there is also a higher risk of pulmonary barotraumatic conditions such as the generation of excessive alveolar pressures. These, in turn, can either lead to alveolar rupture and subsequent leakage of lung gases into the pleural space, or the development of conditions such as mediastinal emphysema. Its use also requires skill and time for set up. Neither method should be used in situations where there is total airway obstruction. Also, there is no evidence that either technique provides adequate protection from problems resulting from the aspiration of throat secretions, blood or vomit.